Well safety valve



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J. s. PAGE,I JR

WELL SAFETY VALVE Nov. 11, 1969 6 Sheets-Sheet 1 Filed June 13. 1967 nlu Nov. 11, 1969 J. s. PAGE, JR 3,477,507

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WELL SAFETY VALVE Filed June 13. 1967 JA/A/ 2 P465 Je ,a a a w.. a. /e f 2 e5 4 7 3 fxzwew a g/ a ,2 www aa h f a 4 7 f 0 f 9 d 2%? @2822 a e m @w22 www y Mp4@ M 0r rae/vens Nov. 1l, i969 J. s. PAGE, JR 3,477,507

WELL SAFETY VALVE Filed June 13, 1967 6 Sheets-Sheet 5 Nov. ll, 1969 J. s. PAGE, JR 3,477,507

WELL SAFETY VALVE Filed June 13, 1967 6 Sheets-Sheet e La. 13. L

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United States Patent O 3,477,507 WELL SAFETY VALVE John S. Page, Jr., Long Beach, Calif., assigner, by mesne assignments, to Cook Testing Co., Long Beach, Calif.,

a corporation of California Filed June 13, 1967, Ser. No. 652,385 Int. Cl. EZlb 33/126; F16k 13/04, 17/34 U.S. Cl. 166-224 28 Claims ABSTRACT F THE DISCLOSURE The disclosure concerns a sub-surface well valve that includes a plug and an expansible and gas containing chamber, such as a bellows, movable for effecting plug closure toward a seat to block upward flow in the well, in response to fluid pressure drop. Further, as the fluid pressure rises so as to collapse the chamber, a portion of the chamber spaced from the plug is bodily movable relative to the seated plug so that the latter may remain seated.

REFERENCE TO PRIOR APPLICATIONS This application is a continuation-impart of application Ser. No. 572,620, filed Aug. l5, 1966, now abandoned, which was a continuation of application Ser. No. 347,542, filed Feb. 26, 1964, now bandoned.

BACKGROUND OF THE INVENTION This invention relates generally to valves usable to control the flow of fluid in pipe or tubing. More particularly, the invention concerns valves of the type char acterized as self-operable to close off flow in tubing when floW conditions are altered.

It is frequently necessary or desirable to control the upward flow of well fluid in tubing in such manner as to pass the flow when it remains below a predetermined value, but to block upward flow should it exceed that value. Such control may be established by connecting in the line a valve using an orifice to create an upward flow pressure differential for actuating the valve; however, erosion may cause the valve to become worn, creating more flow area and thus changing the shut-off point of the valve, so that it may fail to shut-off properly if a break in the tubing occurs. In addition, each well having a different flow rate requires a different orifice area in such a valve. This necessitates stocking many orifices, and careful records of well flow rates and of correct orifices for different wells must be maintained. It is also found desirable that the valve be capable of closing itself when the fluid pressure drops below a predetermined value.

SUMMARY OF THE INVENTION A major object of the present invention is to provide a solution to the above problem, characterized by an unusually simple and effective valve assembly and mode of operation as will be brought out in detail. The novel assembly provided to control the flow of fluid in surface or sub-surface piping or tubing basically comprises a tubular member, a generally annular flow passing seat carried in said member, and means including a plug movable for effecting relative closure of the plug and seat to restrict fluid flow within the member when the fluid pressure drops below a predetermined value, and also when the flow of fluid within the member reaches a predetermined ow rate. The last mentioned means typically includes an expansible bellows mounting the plug within the tubular member or body for effecting plug closure against the seat to restrict fluid flow within the member in response to bellows expansion when the fluid pressure drops below the predetermined value, as during a break in the tubing downstream of the valve. Also, the plug and bellows are bodily movable toward the seat, as for example when the flow of well fluid within the tubular member or body exceeds the mentioned predetermined flow rate.

One important advantage of this bellows valve principle where the valve is incorporated in well tubing is that it shuts off at a decrease in well pressure regardless of the well flow rate. While the user may have many wells with varying amounts of flow, he can set the valve in each well to shut off at a predetermined low pressure, and at such time as damage may occur to any well the valve therein will close upon the occurrence of that predetermined low pressure.

Another important object of the invention is to prevent pressure rise created collapse of the bellows effecting opening of the valve, after bellows expansion acting to close the valve. In accordance with the invention, the bellows is mounted by a bodily movable carrier typically held in a downward position by yieldable means such as a spring. When the valve plug moves upward to close the valve and the shut-in pressure below the plug increases on the expanded bellows, the latter collapses from the bottom up, and against the yieldable force of the spring, while the valve plug remains in closed position.

It is a further object of the invention to provide the plug with an upwardly tapering generally conical upper surface which is movable upwardly when the plug closes toward the seat, there also being a passage or clearance for well fluid to flow past the plug and bellows and for flushing foreign particles off the tapering upper surface of the plug when it is retracted from the seat. As a result, the problem of sanding acting to prevent desired bodily movement ofthe plug and bellows is avoided.

Other objects and advantages of the :invention include the provision of structure supporting the bellows carrier to receive upward thrust exerted by the upward flow of well fluid in the tubing, thereby to bodily displace the bellows and plug upwardly toward the seat; yieldable means urging the carrier downwardly and away from the Seat in order to provide resistance to plug closure in response to upward flow created thrust acting in the carrier, for establishing a desirably higher limit of flow at and above which the plug will close against the seat; the protection of the bellows against abrasive wear during upward flow of well fluid adjacent thereto; the precharging with both gas and liquid so that the bellows cannot be collapsed to the extent of causing damage to it; the provision on the tubular member or body of spring finger urged latches connectible to well tubing or to a sub in series with such tubing and into which the member is receivable; the provision of an internally enlarged tubular sub to receive the plug and bellows assembly for increasing the flow capacity of the valve; and the provision for connection of the tubular body itself in series with a surface or sub-surface flow line so that the bodily movable plug and bellows are permanently retained in the line to operate as described.

Another object of the invention is to provide a valve that will have a fail-safe feature characterized in that if the charge in the bellows leaks and equalizes with the pressure of fluid in the tubing, the inherent spring force ot' the bellows will cause the bellows to expand, closing the valve.

These and other objects and advantages of my invention, as well as other details of an illustrative embodiment will be fully understood from the following detailed description of the drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a vertical elevation sectioned and broken away in part to show a string of tubing into which the assembly of the invention is receivable, together with installation and retrieval equipment at the well head;

FIGS. 2a and 2b comprise enlarged vertical elevations showing installation of the assembly in tubing:

FIG. 3 is a vertical section showing the installed assembly wherein the valve plug has just closed in response to bellows expansion;

FIG. 4 is a vertical section showing the manner in which the assembly is typically unlatched from the tubing string;

FIG. 5 is an enlarged section taken on line 5 5 of FIG. 3;

FIG. 6 is an enlarged vertical section showing the ported and valved inlet to the bellows carrier and operable to control admission of pre-charging iluid to the bellows;

FIG. 7 is a vertical half section showing the valve plug closed and the `bellows collapsed upwardly;

FIGS. 8a and 8b show a modied valve assembly being run into a well;

FIGS. 9a and 9b show the FIG. 8 valve assembly installed in a well, with the valve plug closed;

FIGS. 10 and 11 show another modied valve assembly; and

FIG. 12 illustrates another modified valve assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, the valve assembly will be understood as being downwardly receivable in a production tubing string 10 which extends downwardly within well casing 11. The latter typically extends upwardly to the well head where it mounts the control equipment generally designated at 12. Such equipment is illustrated to include a main valve 14 for controlling the upward ow through the tubing, a production flow control valve 15 in line 16, and an inlet ow control valve 17 through which uid may be pumped at 18 to the annular space 19 Within the well and outside the tubing 10. For example, uid may be pumped into space 19 in order to effect upward flow within the string 10, for purposes as will appear.

The well head assembly 12 also includes a iiexible line 120 through which liuid pressure may be pumped at 121 downwardly into the string 10 via the intermediate structure generally designated at 122. The latter includes shutolf valves 123 and 124 at opposite sides of a releasable lubricator coupling 125 through which -access may be had to the interior of the conduit 126 in order to insert and remove the tools as will be described, such apparatus including the valve assembly 20.

Referring now the FIGS. 2a and 2b, the valve assembly 20 is shown being run downwardly in the tubing 10. The insert assembly includes a tu-bular member or body 21 having a generally annular seat 22. The latter may be located within a carrier ring 23 held at the lower terminal of body part 21a and within the bore 24 of body part 2lb, which is attached to part 21a at threading 25. Seat 22 typically comprises a plastic or rubber ring.

A plug is carried for bodily movement between a down position in which the plug is spaced below the seat 22, and an up position in which the plug engages the seat to prevent or block upward flow therethrough. In the form of the invention shown, the plug 26 is seen in its down position in FIG. 2b as having an upwardly tapering generally conical upper surface 27 movable upwardly when the plug closes toward the seat, the latter condition being illustrated in FIG. 3,

Means for effecting plug movement toward the seat may be considered to include bellows 28 which is axially expansible when the fluid pressure outside the bellows drops below the predetermined pressure of uid such as gas within the bellows. Such means may also be considered to include a bodily movable carrier 29 seen in FIG. 2b as mounting the bellows at 30 and as tapering downwardly at 131 to receive upward thrust exerted by the upward flow of well fluid in the tubing. A carrier stern 31 projects downwardly through support or guide structure 32 extending transversely across the lower interior 33 of the tubular part 2lb, and yieldable means such as a spring 34 urges the carrier downwardly and away from the seat. 'Spring 34 typically ts between structure 32 and a ring ange 35 on the lower terminal of stem 31. FIG, 7 shows the plug 26 closed on the seat 22, and the bellows collapsed upwardly, as by an increase in shut-in pressure after initial closure of the plug as seen in FIG. 3.

The carrier contains porting 36 controlled by a valve 37 for charging the bellows with internal uid establishing a predetermined pressure value characterized in that they bellows will effect closure of the plug against the seat when the fluid pressure outside the bellows drops below said value. The charging fluid typically includes gas and suthcient oil to prevent damaging collapse of the bellows. Valve 37 typically comprises a tire valve threaded into the entrance of port 36, and a soldered plug or other protective cover 39 is emplaced over the port mouth. As seen in the drawings, the port extends upwardly through the stem and the tapered portion of the carrier to the lower end of the bellows FIG. 5 shows the polygonal or hexagonal opening 40 in guide structure 32 for passing the tubular stem 31, with clearances 41 adapted to remove foreign particles such as sand from between the stem and guide by ushing action.

It will also be noted that an annular passage 42 is formed between the bore of tubular part 2lb and the means including plug 26, carrier 29 and a skirt 43 protectively encompassing the bellows 28 between the plug and carrier. Passage 42 passes the well fluid and also foreign particles settling oft" the plug taper 27 when the plug is retracted from the seat. Accordingly, detrimental sanding of the opening 44 between the plug and seat is prevented, assuring positive closure Of the valve plug against the seat. The skirt 43 is typically carried by the plug at 45 and has a loose slip t about the car- -rier at 80.

In operation, should the static pressure of fluid at the valve depth drop below the pressure at which the bellows tends to expand, the plug will be seated in response to bellows expansion irregardless of the rate of upward ow of uid about the open plug. On the other hand, should such upward ow be such as to exert upward force on the carrier 29 overcoming the spring 34 and the weight of the plug, carrier and bellows, the latter will move as a unit and bodily upwardly to effect seating of the plug at and above the predetermined critical upward iiow rate, even though the bellows may remain collapsed. One reason why these functions may be carried out automatically and in the manner described is because the bellows is mounted for bodily movement with the plug. It is also noted that the assembly may be run into a well through a lubricator and subjected to the shut-in pressure of the well. The bellows at that time will be collapsed, and the plug open allowing the assembly to run down into the well. Whenever the valve plug moves up to close the seat, an increase in shut-in pressure suflicient to collapse the bellows will collapse it from the bottom end up so as not to disturb the closure of the valve. The Valve may be opened by increasing the pressure above the plug and in the tubing to displace the plug and bellows bodily downwardly.

Referring to FIGS 2a and 3, the assembly 20 includes holding means in the form of a collet generally indicated at 46, which is releasably engageable with tubing terminals to allow lowering of the assembly in the tubing string 10 and to` resists raising of the assembly therein. Typically, the holding means includes a series of latches 47 exposed for engagement with tubing terminals as indicated at 48 and 49. In this regard, the holding means is also seen to include outwardly urged spring lingers 50 carrying the latches 47 and projecting generally axially opposite the upper end of the body part 21a in FIG. 2a during downward travel of the assembly within tubing. In this configuration, the lingers 50 urge the latches 47 outwardly to ratchet into and out of the grooves 51 formed between the terminals 48 and 49 of successive tubing stands coupling together by collars 52 as shown in FIGS. 2-4, the tapered lower shoulders 53 of the latches camming against and over the terminals 48.

The holding means or collet 46 previously mentioned also includes a carrier for the spring fingers 50, the carrier being attached to the valve body part 21a so as to allow relative axial movement of the holding means and body. In the example shown, the carrier 54 is in the form of a ring extending about the body directly below body flanging 55, which is slotted to receive fingers 50. A connection is provided between the holding means and body and is characterized as forcibly releasable or detachable in response to sufficient exertion of lifting force tending to raise the body relative to the carrier at times when lifting of the holding means is resisted, as for example by latching thereof to the tubing. One such connection is shown at 56 in the form of inward facing detent shoulders on the spring fingers 50 and spaced about the upper terminal lip 156 of the body 21a in FIGS. 2 and 7.

Upon sullicient lifting force exertion by the body, with upward travel of the holding means 46 prevented, the lip 156 will cam the detent shoulders 56 outwardly, as permitted by flexing of the lower extents 157 of lingers 50, to allow relative axial -collapsing of the body from the lower or extended position as shown in FIG. 2 to the upper or collapsed position shown in FIG. 3. During collapsing movement the carrier 54 lands on the ring seal units 57 which in turn lands on the upper end of the body part 2lb as seen in FIG. 3, thereby to further energize the seal. Collapsing movement ceases when upper terminal 156 lands against stop shoulder 84 on holding means 46. In this regard, the unit 57 seals olf between the periphery of the valve body part 21a and the bore 58 of the tubing 10, in up position of the valve body relative to the holding means 46.

Referring back to FIG. 2, liuid pressure responsive means is provided for engagement with the assembly, displacing it downwardly within the well tubing, such means typically including a ram generally indicated at 59 and having a lower terminal 60 contacting the cupped upper terminal face 90 of the body part 21a. The ram includes an elongated rod 61 projecting downwardly into the assembly 20 from an upper zone at which the ram carries upper and lower sealing cups 62 and 63, suitable attachment to the ram being provided at 64 and 65. The packing cups are adapted to be fluid pressure activated for sealing off against the tubing bore 58, and in this regard downward fluid pressure exertion on the cups results in downward displacement of the assembly 20 to selected position within the tubing. Downward thrust may be transmitted by the ram to the assembly 20 through a pusher 163 on the rod 61 and having a lower lip 164 engaging the upper terminals 165 of the holding means 46, and urging them inwardly sufficiently to help the latches 47 cam over the tubing terminals 48.

Upon arrival of the assembly 20 at selected depth, the latches 47 spring outwardly into the groove 51 as seen in FIG. 3 whereby upward displacement of the holding means 46 is prevented by engagement of the latch upper shoulder 66 with the lower terminal 49 of the upper tubing stand shown. Thereafter, lluid flow may be effected upwardly through the assembly 20 to lift the ram 59 away from the assembly 20, the ram being retrievable through the coupling 126 seen in FIG. 1. When the upward fluid ilow rate is increased sufficiently, the plug 26 will seat at 22 and collapse or retract the valve body part 21a and 2lb upwardly relative to the holding means 46 and to the position shown in FIG. 3. Under these circumstances, the spring lingers 50 become blocked against inward collapse by the periphery of the valve body part 21a, whereby inadvertent unlatching of the assembly from retention within the tubing is assured. The valve assembly may then be operated in the tubing for as long as desired to control the upward flow of lluid therein, blocking such flow when it increases to a level or value within a predetermined range.

The invention also provides for retrieval of the valve assembly 20 as by upward displacement thereof to the coupling 126 for removal, inspection and replacement if necessary. In order to effect such retrieval, the valve assembly is first unlocked from the position shown in FIG. 3. For this purpose, the valve body 21 is downwardly extended from collapsed condition, as for example by inserting a plunger into the tubing 10` and pumping it downwardly to a position where the plunger lands on the cupped surface 90 of body part 21a. A typical plunger is shown at 70 in FIG. 4 and may have the same construction as ram 61 so that continued downward pressure exertion against the plunger extends the valve body with respect to the holding means 46, and to the position shown in FIG. 4. In this regard fluid may be pumped at 18 to the annulus 19 for downward flow around packer 82 and then back up through tubing 10 to remove the plunger upwardly.

The assembly 20 is simultaneously unlatched from the tubing in order to prepare it for upward displacement and retrieval with the plunger. For this purpose, a tubular grip ping member such as is shown at 73 in FIG. 4 is carried for axial movement along the plunger rod reduced diameter extent 172 and is urged downwardly by a spring to forcibly endwise engage the upper terminal connections 74 integral with the spring fingers 50. As the plunger is forced downwardly, the compression in spring 80 increases sufficiently so that when the latches cam inwardly as caused by downward movement of the plunger the gripper 73 suddenly releases downwardly to further collapse the connections 74 and the latches 47 inwardly to traveling position shown in FIG. 4. Suitable gripping connection between the member 73 and the connections 74 is provided, by the mutually interengaged serrations 76 thereon. Finally, fluid is caused to flow upwardly through the assembly 20, closing plug 26 against seat 22 and lifting the plunger and the entire assembly 20 by which it may be upwardly removed or retrieved from the tubing.

Referring to FIGS. 8a and 8b, the valve assembly 220 is shown being run downwardly in the tubing 210 and into a tubular sub 211 having a threaded box 212 and pin 213 respectively connected with the pin and box ends 214 and 215 of tubing stands. Sub bore 216 is enlarged at 217, thereby providing the sub with a cylindrical passage enlargement generally indicated at 218 for llowing fluid outwardly of the valve assembly 220 and lengthwise of the sub.

The valve or insert assembly 220l includes a tubular member or body 221 that includes upper part 221a and lower part 221b, the latter being attached to the former at the general location 222. External thread 223 on the lower body part 221b is screwed completely through internal thread 224 on the upper body part 221er, to allow limited telescoping of the body parts in order to energize the packing ring 225 after attachment of upper part 221a in the sub. Thus, for example, as seen in FIG. 9a, thrust exerted upwardly by lower body part 221b effects such limited telescoping as to energize ring 225 retained between rings 226 and 227, thereby to seal off between the lower part 221b and the sub bore 216.

A plug 228 is carried for bodily movement between a down position in which the plug is spaced below a seat 229 as seen in FIG. 8a, and an up position in which the plug engages the seat to resist or block upward flow therethrough. Seat 229 typically comprises an annular plastic or rubber ring capable of being squeezed to increase its pressure sealing engagement with the plug annular periphery at 230. In this regard, the seat 229 is confined against escape when engaged by the closed plug, and means is provided to receive pressure transmitted by the plug for pressurizing the seat to seal against the closed plug. Such means may typically include upper and lower metallic rings 231 and 232 movable above and below seat 229 on the counterbore 233, yet retained against disassembly by fastener 234. Plug flange 235 is axially engageable with lower ring 232 to effect squeezing of the seat 229. The plug also has an upwardly tapering, generally conical upper surface 236 movable upwardly when the plug closes toward the seat.

Means for effecting plug movement toward the seat may be considered to include internally pressurized bellows 238 similar to bellows 28 previously described, and bodily movable carrier 239. The latter'mounts the bellows at 240 for axial bodily movement, and it tapers downwardly at 241 toward an integral carrier stern 242 projecting downwardly through support or guide structure 243. A compressor spring 244 urges the carrier 239 downwardly and away from the seat 229, the spring being retained between nut 245 and locknut 245:1 on the lower portion of the stem and the guide structure 243, which extends as a web across the lower interior of tubular body part 221b.

In FIGS. 9a and 9b the bellows is seen in expanded condition as would occur upon a drop in flow pressure at the valve and below the internal pre-charge pressure of the bellows, the plug 228 being closed against the seat. Carrier 239 contains porting 246 controlled by tire valve 247 for charging the bellows with internal fluid pressure of predetermined value.

Fluid flowing upwardly not only passes within the annular passage enlargement 218, but also through the passage 248 formed between the bore 249 of tubular part 221b and a skirt 250 protectively encompassing the bellows 238, indicating increased flow capacity over the valve assembly of FIGS. 2-7. Skirt 250 is typically carried by the plug at 251, and has a loose slip fit about the carrier at 252. The tubular body part 221b has a series of circularly spaced side ports 253 communicating between the upper interior of passage 218 and the interior of tubular body part 221b at the top of the plug in fully retracted position, as seen in FIG. 8a. Accordingly, the upward flow within passage enlargement 218 passes through ports 253 and merges with the upward flow in passage 248 as the flow approaches the region of the seat 229.

When closing of the valve assembly is to be made independent of upward flow velocity, the total flow area of passage 248 and enlargement 218 is made at least as large y as the total flow area at the seat, i.e. the area of the opening defined by the seat annulus. When the total flow area of passage 248 and enlargement 218 is less than the flow area at the seat, the valve will also close in response to upward flow velocity above a predetermined value. In any event, should the static pressure of fluid at the valve drop below the pressure at which the bellows tends to expand, the plug 228 will approach the seat irregardless of the rate of upward ow of fluid about the open plug. Thereafter, an increase in fluid pressure sufficient to collapse the bellows will collapse it from the bottom end up so as not to disturb the closure of the valve. The valve may then be opened by increasing the pressure above the plug to displace the plug and collapsed bellows downwardly and bodily.

Referring to FIG. 9a, the valve assembly includes holding means 254 having latches 254a exposed for engagement in annular grooving 255 formed in the sub 211 below interior ange 256. The holding means also includes outwardly urged spring fingers 257 carrying the latches 254a, the fingers being integral with body part 221a. An external annular shoulder 258 on body part 221a is engageable with sub internal shoulder 259 to effect landing of the valve assembly therein at a location permitting of outward displacement of the latches 254a into the grooving 255. Thereafter, the internal ange 256 limits upward displacement of the valve assembly in the sub, with the latches received in grooving 255.

FIG. 8a shows the valve assembly being run into a Well as by a ram generally indicated at 260. The ram mandrel is enlarged at forward location 261 and is pinned at 262 to the internal ange 263 of valve body part 221a, there being an opening 264 through the enlargement 261 to pass well fluid upwardly therethrough as the ram descends in the tubing 210. A keeper 265 is pinned on the ram mandrel portion 266 at 267, the keeper having a tapered recess wall 268 engageable with the tapered projections 2619 on fingers 257 to maintain the fingers and latches 254a sufliciently inwardly retracted as not to interfere Iwith downward running of the valve assembly through tubing 210 and to sub 211. Upon landing of the valve assembly in the sub, the pins 262 and 267 are sheared, releasing the keeper 265 which inturn releases the finger extensions 269 `allowing outward displacement of latches 254a into grooving 255, and also releasing the mandrel enlargement 261 from the valve assembly 220. Engagement of a mandrel flange 271 `with body internal ange 263 limits further downward travel of the mandrel in the valve assembly after shearing of the pins as described. Thereafter, the ram unit 261 may be upwardly retrived. A recess 272 in the lower terminal of the ram is engageable with the plug taper 236 should the plug be closer to the seat 229, it being contemplated however that the fluid pressure in the well will be suicient during running of the valve assembly by the ram 261 to hold the bellows 238 collapsed and the plug 228 in open position. Downward thrust may be communicated to the ram 2'61 in any suitable manner.

In the modification illustrated in FIGS. 10 and 1l the valve assembly 300 includes a tubular member or body 301 in the form of a sub having a threaded box end 302 and 303 respectively connected in the pin ends 304 and 305 of flow line conduit members 306 and 307. The valve assembly includes a tapered plug 308 mounted by a bellows 309, these elements generally corresponding to elements 228 and 238 of FIGS. 8 and 9.

Plug 308 is carried for bodily movement between a retracted position as seen in FIG. l0 and the advanced or seated position of FIG. l1. The annular seat 310 is generally the same as seat 229 in FIGS. 8 and 9, it being confined against escape by the closed plug. Metallic rings 311 and 312 at opposite ends of the seat are movable on counterbore 313 of sub internal flange 314. When plug flange 315 forcibly engages ring 312, the latter is movable to squeeze the seat 310 for increasing its pressural sealing engagement `with plug cylindrical face 316, as viewed in FIG. 11.

The bellows 309, which is internally pressurized and expansible to displace the plug toward the seat, is mounted on carrier 317 for axial bodily movement, as for example between the positions as seen in FIGS. l() and 11 in each of which the bellows is collapsed. A typical sequence includes expansion of the bellows from the FIG. 10 position to displace plug 308 to the broken line position 318 while carrier 317 remains in position, and subsequent collapse of the bellows while the plug remains seated, and to the FIG. ll position.

Carrier 317 includes an integral stem 319 projecting through support or guide structure 320 including tapered baffle 321 centered coaxially in the body 301, as by mounting ring 322 carried by ribs 323. The latter are circularly spaced about the bellows in annular passage 324 formed between the sub bore 325 and a skirt 326, protectively encompassing the bellows and carried by plug 308 at 327. When the plug is retracted from the seat as in FIG. l0, the flow toward the seat may pass between the ribs and through passage 324, as indicated by arrow 328. At such times, the static pressure typically exceeds the internal pressurization of the collapsed bellows, and a compression spring 329 on stem 319 holds the carrier 317 In the modification illustrated in FIG. 12 the valve or.

insert assembly 420 is of generally the same construction as seen in FIG. 3. Thus, it includes body parts 421a and 42111; tapered annular seat 422 on ring 423; and plug 426 having tapered generally frusto-conical upper surface 427 movable upwardly when the plug closes toward the seat. The plug includes upper and lower parts 426a and `42612 interconnected at 428, with lower part 426b being mounted on bellows 429.

By-pass porting extends downwardly at 430 within the plug, and laterally at 431, to communicate via the plug interior between the body interior at 432 and 433 above and below the seat and outside the plug. Also, rupturable means is provided normally to block the by-pass porting, such means typically taking the form of the frangible closed end tube insert 434 projecting laterally within porting 430 in downwardly and axially spaced relation from the top of the plug. Thus, the insert is located to be ruptured by a tool 435 lowered within the body toward the plug when the latter is seated. Such rupture establishes by-pass communication across the plug, for equalizing the uid pressures above 'and below the seated plug when it is desired to open the valve.

The remainder of the structure of the FIG. l2 valve is similar to that described in connection with FIGS. 2 and 3. Note in this regard the skirt 440` protectively encompassing the bellows, and the guide lugs 441 on the skirt.

I claim:

1. An assembly operable to control the flow of fluid, comprising a tubular member, a generally annular flow passing seat in said member, and means including a plug and an expansible and gas containing chamber movable to effect plug relative movement toward said seat to restrict fluid flow past the -chamber and plug and toward the seat within said member in response to expansion of said chamber when the pressure of said fluid drops below a predetermined value, the chamber having a portion remote from the plug that is free to move relatively toward the seated plug in response to a fluid pressure rise acting to collapse the chamber.

2. An assembly operable to control the flow of fluid, comprising a tubular member, a generally annular flow passing seat carried in said member, and means includ ing a plug and an expansible and gas containing bellows movable for eilecting plug relative movement toward said seat to restrict fluid flow past the bellows and plug and toward the seat within said member in response to expansion of the bellows when the pressure of said fluid drops below a predetermined value, said means including a bodily movable carrier mounting the bellows and free to move with -collapse of the bellows toward the seated plug in response to a fluid pressure rise acting to collapse the bellows.

3. The assembly of claim 2 including well tubing axially receiving said member so that uid flow within said tubing is controlled by said plug and seat.

4. An assembly operable to control the ow of fluid in well tubing, comprising an axially extending tubular body, a generally annular seat carried in said body, and means including a plug and a pressurized bellows mounting the plug for effecting plug closure toward said seat to block fluid flow through the seat in response to expansion of the bellows when the fluid pressure drops below a predetermined value, the plug and bellows both being axially bodily movable and a portion of the bellows remote from the plug being movable to collapse toward the seated plug in response to a fluid pressure rise acting to collapse the bellows, said means including a bodily movable carrier mounting the bellows, and exposed t0 receive thrust exerted by the ilow of Well fluid past the carrier and toward the seat.

5. The combination as defined in claim 4 in which the plug has an upwardly tapering generally conical upper surface and is movable upwardly when the plug closes toward said seat, said means and body forming a passage for well fluid flowing past the plug and bellows and for flushing foreign particles off said tapering upper surface of the plug when the plug is retracted from said seat.

6. The combination as defined in claim 4, in which the assembly includes yieldable means urging the carrier away from said seat.

7. The combination as defined in claim 4, in which the assembly includes a skirt protectively encompassing the bellows between the plug and carrier, said skirt and the body bore forming a passage outwardly of the skirt for passing the flow of well fluid when the plug is retracted from the seat, said assembly including a ring seal carried by said body to pack olf between the tubular body and the tubing bore into which said body is inserted.

8. The combination as defined in claim 4, in which the carrier contains valve controlled porting for charging the bellows with internal fluid establishing said predetermined pressure value.

9. The combination as defined in claim 4, in which the assembly includes holding means having outwardly urged latch structure receivable in well tubing bore grooving when the body is displaced downwardly in the tubing to register the latch structure and grooving, thereby t0 position the assembly in said tubing.

10. The combination as defined inlclaim 9, in which said body has an axially extended position with respect to said holding means in which said latch structure is inwardly collapsed to allow lowering of the assembly in a tubing string, and an axially retracted position with respect to said holding means in which said latch structure is displaced outwardly for latching engagement with a tubing terminal.

11. The combination as defined in claim 10, in which said holding means includes spring ngers carried by and projecting upwardly with respect to said body, the fingers supporting said latch structure and having upward terminal connections adapted to be grasped by a tool acting to collapse said lingers inwardly allowing upward retrieval of the insert assembly in the tubing.

12. The combination as defined in claim 11 including iiuid pressure responsive means having a ram receivable within the tubing to engage and displace the assembly downwardly in the tubing, the ram projecting inwardly of said spring lingers.

13. In sub-combination, an axially extending tubular body, a generally annular ow passing seat in said body, and means including a plug and an expansible and gas containing chamber carried in said body for effecting plug closure relatively toward the seat to restrict fluid oW through the seat in response to axial bodily movement of the plug toward the seat when the flow of uid within the body and past the chamber and plug exceeds a predetermined rate, the chamber having a portion remote from the plug that is free to move relatively toward the seated plug in response to a fluid pressure rise acting to collapse the chamber, the plug having a generally conical surface presented toward the seat as the plug approaches the seat, said means and body forming a passage for passing well uid flowing toward the plug and for freely passing foreign particles when the plug is retracted from said seat to allow said particles to leave said plug conical surface.

14. The sub-combination as dened in claim 13 in which said means includes a plug carrying stem, and in- 11 cluding a stem guide carried by said body to guide axial movement of the plug.

15. The sub-combination as defined in claim 14 including a spring urging the stem downwardly to carry the plug away from the seat.

16. The combination as defined in claim 4 including said tubing and a tubular sub connectible in series with the tubing for receiving said assembly, said sub having a passage enlargement to pass uid flowing outwardly of the bellows and toward the seat.

17. The combination of claim 16, in which the total flow area outwardly of the bellows is at least as great as the total ow area at said seat.

18. The combination of claim 16, in which the tubular body is spaced outwardly of the bellows and inwardly of the sub bore at the periphery of said passage enlargement said body containing side ports to pass the ow as it leaves said passage enlargement and flows toward the seat.

19. The combination of claim 16, in which said sub and said body have interengageable shoulders for landing the body in said sub with the bellows located inwardly of said sub bore at the passage enlargement.

20. The combination as `defined in claim 4 including said tubing, and in which said assembly includes means for connecting said body in series with said tubing with said plug and bellows retained in said body.

21. The combination as defined in claim 20, in which the assembly includes a skirt protectively encompassing the bellows, the body having a bore and the skirt and bore forming a passage outwardly of the skirt for passing the ow of well fluid when the plug is retracted from the seat, the skirt being bodily movable axially and the assembly including ribbing in said passage between the skirt and body bore.

22. The combination of claim 4, in which said seat is non-metallic and is confined against escape when engaged by the closed plug, and including means to receive pressure transmitted by the plug for pressurizing the seat to seal against the closed plug.

23. The combination of claim 1, in which the seat comprises a non-metallic ring in the path of plug upward movement.

24. The combination of claim 1, in which the seat comprises a radially deformable ring, and including means to receive pressure transmitted by the plug for pressurizing the seat to deform inwardly and seat against the periphery of the plug.

25. The combination of claim 4, in which the body extends vertically, and including by-pass porting to communicate via the plug interior between the body interior above and below the seat and outside the plug, and rupturable means normally blocking said by-pass porting and located to 'be ruptured by a tool lowered within said body toward the plug when seated against the seat.

2-6. The combination of claim 25 `wherein the by-pass porting extends vertically downwardly within the plug from the top thereof, and said rupturable means projects in said porting in downwardly spaced relation from the top of the plug.

27. An assembly operable to control the fiow of fluid in well tubing, comprising an axially extending tubular body, a generally annular seat carried in said body, and means including a plug and a pressurized bellows mounting the plug for effecting plug closure toward said seat to block uid flow through the seat in response to ex pansion of the bellows when the fluid pressure drops below a predetermined value, the plug and bellows :both being axially bodily movable and a portion of the bellows spaced from the plug being bodily movable realtively toward the seated plug in response to a fluid pressure rise acting to collapse the bellows.

28. The assembly of claim 27 including a Carrier mounting the bellows and extending therebelow, and porting in the carrier and communicating with the interior of the bellows for charging the bellows with internal fluid establishing said predetermined pressure value.

References Cited UNITED STATES PATENTS 1,178,422 4/1916 Smolarek 137-466 1,741,489 12/1929 'Watts 137-504 XR 2,298,150 10/1942 Newton 137-504 XR 2,890,859 6/1959 Garrison 137-504 XR 3,252,476 5/1966 Page 137-458 3,389,718 6/1968 Johnson et al. 137-458 XR M. CARY NELSON, Primary Examiner R. I. MILLER, Assistant Examiner U.S. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,477,507 November ll, 1969 John S. Page, Jr.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading to the printed specification, line 5,

"California" should read Nevada Column l, line Z7, "bandoned" should read abandoned Column 4, line 72, "resists" should read resist Column 8, line Z5, "retrived" should read retrieved Signed and sealed this 27th day of Cctober i970.

(SEAL) Attest:

Edward M. Fletcher, Jr. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner of Patents 

